Sudoku solver

[Frank Millman]

"Dave Angel" <davea at davea.name> wrote in message 
news:551557B3.5090102 at davea.name...
>
> But now I have to disagree about "true Sudoku puzzle."  As we said 
> earlier, it might make sense to say that puzzles that cannot be solved 
> that way are not reasonable ones to put in a human Sudoku book.  But why 
> isn't it a "true Sudoku puzzle"?
>

It seems you are correct.

According to Wikipedia http://en.wikipedia.org/wiki/Glossary_of_Sudoku -

A puzzle is a partially completed grid. The initially defined values are 
known as givens or clues. A proper puzzle has a single (unique) solution. A 
proper puzzle that can be solved without trial and error (guessing) is known 
as a satisfactory puzzle. An irreducible puzzle (a.k.a. minimum puzzle) is a 
proper puzzle from which no givens can be removed leaving it a proper puzzle 
(with a single solution). It is possible to construct minimum puzzles with 
different numbers of givens. The minimum number of givens refers to the 
minimum over all proper puzzles and identifies a subset of minimum puzzles.

So what I am talking about is called a "satisfactory" puzzle, which is a 
subset of a "proper" puzzle.

Frank